From: Joe Van Dyk <joevandyk@...>
Date: 2005-12-08T23:54:02+09:00
Subject: Re: do/end vs braces

On 12/8/05, James Edward Gray II <james@grayproductions.net> wrote:
> On Dec 8, 2005, at 8:13 AM, Joe Van Dyk wrote:
>
> > On 12/8/05, Steve Litt <slitt@earthlink.net> wrote:
> >> Hi all,
> >>
> >> It looks to me like when you use an iterator (each for instance),
> >> you can make
> >> the block either from a do/end pair, or from curly braces. All
> >> things being
> >> equal, I'd greatly prefer to use do/end. Are there any differences
> >> in runtime
> >> speed, capabilities, or Rubyness?
> >
> > Typically,
> >
> > 5.times { |i| puts i }
> >
> > 5.times do |i|
> >   puts i
> > end
> >
> > Generally people save do .. end for multiline stuff.  Don't think
> > there's a difference in speed.
>
> Another convention some use is that { ... } are for the times when
> you care about the return value and do ... end is for when you're
> interested in the side effects.  For example:
>
> sum = [1, 2, 3].inject { |sum, n| sum + n }  # return value
>
> File.open("total.txt", "w") do |file|  # side effects
>    file.puts sum
> end

Good point.  And also use { ... } if you want to do crazy chains like

[1, 2, 3].collect { |a| i * a }.each { |a| puts a }

Joe